An entity such as a business organization will often maintain a network for its computing systems. One type of network structure is a distributed network structure. In a distributed network structure, several sub-networks work under the direction of several different network controllers. This is opposed to a centralized structure where traffic from every computing system is managed from a central location. Distributed network systems are more efficient because broadcast traffic is only broadcast to smaller sub-networks rather than the entire network maintained by the organization. This reduces costs, uses less bandwidth, and allows for greater scalability. These sub-networks are commonly referred to as local networks.
The local networks maintained by an organization typically correspond to units within an organization. For example, the engineering department of that organization may be under one local network while the accounting department is under another local network. A network user belonging to a particular department is often issued a client computing device, such as a laptop, that is configured to work on the network of the department to which that user belongs. This network is referred to as the user's home network.
One challenge that arises with distributed network systems is managing network traffic when a user roams from one local network to another. For example, if a user from the engineering department brings his or her laptop to the accounting department and attempts to connect to the wireless network there, that laptop will no longer have access to its home network. Even if the laptop is granted access to the accounting department network, it may not have access to its home network and the services provided by that home network.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.